I have a column series with multiple data columns defined in the yField property that will give me a grouped column chart as opposed to a stacked column chart. When I had just 1 column defined in the yField, I could give the column a gradient using the renderer function for the series:

However with multiple yFields defined in the series, I am having difficulty trying to find which field I am drawing at the time. The i parameter in the renderer function tells me which bar I am drawing for the whole chart and the StoreItem shows me what record, but what I would like is to tell me which yField it is drawing. Any ideas?

this = the series so I have the yField array to work with. The variable i in the function tells me which column in the chart it is rendering- if I have 50 columns total then i can be from 0 to 49. So if the renderer passes i = 21 and yField array length = 2 then i % this.yField.length or 21 % 2 = 1 which tells me that I am rendering the 2nd item in the group (0 based). I then set the fill = 'url(#gradient1)'. It seems to work for now.